Summary: Zoro had promised to spill blood for his captain. Back then he imagined the extent to that was battlefields, sword wounds, dying at Luffy's side against impossible enemies. He never expected that promise would mean sitting quietly beneath moonlight while his captain drank directly from his veins.
The Thousand Sunny was quiet in a way it never was during the day. No laughter echoing across the deck, no footsteps pounding overhead, no shouting from the rowdy members that made up the Straw Hat Pirates.
Most of the crew had long since gone to sleep. The aquarium bar lights were dimmed, the kitchen cold, the galley quiet, and even the usual nighttime chatter from the men's quarters had died hours ago.
Zoro sat in the crow's nest, half asleep and half awake. His swords rested beside him, ready to be drawn in the face of any adversary daring enough to climb aboard the ship.
The sea tonight was calm in all directions, the nightwatch uneventful, so he allowed himself to rest his eyes. Zoro's discipline was refined enough to keep him aware of his surroundings even as he dozed off. So the sound of someone using the ladder to reach the watchtower/gym didn't go undetected.
Luffy emerged before him, rubbing one eye, raven hair sticking out in every direction. The captain's stomach twisted painfully as raw hunger clawed at him. It was enough to make his fangs come out on their own.
This hunger ached deeper than his ordinary hunger, which was already insatiable enough.
Zoro finally cracked his good eye open and met the restless expression on the captain's face. The skin beneath Luffy's eyes was darkened by fatigue that he still needed to sleep off, which begged the question of what he was doing up in the first place.
Zoro closed his eye again and crossed his arms over his chest.
"It's late." The swordsman gruffly scolded, but there was no real bite to his words. He roughly surmised it was somewhere between 2:00 and 4:00 in the morning. "What're you doing awake? Did Brook fart?"
Brook's gas, as paradoxical as it was, could clear the men's quarters as quickly as a drill sergeant snapped a gaggle of soldiers to attention. It was all that milk he drank.
"I'm hungry," Luffy said instead.
Zoro scoffed slightly. Of course he was.
Although why Luffy was bothering to announce it to him at all was beyond him. Normally, he'd just go into the kitchen to help himself, bypassing Sanji's comically large mousetraps, which their cook was constantly having to upgrade since Luffy kept finding ways around them.
Sanji had talked about resorting to a security alarm, but no one else was on board with the idea of getting violently pulled from sleep by a blaring alarm simply because their captain had tripped the security to grab a midnight snack. Sanji argued it was a matter of preserving food that would otherwise be wolfed down by Luffy, and even backed it with the importance of rationing food while at sea, but his suggestion was vetoed.
"Do I look like that stupid cook?" Zoro mumbled. "Ask Sanji in the morning."
Zoro waited for the string of whines, but tonight, despite being denied food, Luffy was oddly quiet. That withdrawn silence should have been Zoro's cue, because they all knew how much Luffy hated asking.
But truthfully, the Vice-Captain was more asleep than awake.
"Zoro," Luffy repeated, "I'm hungry."
The shy, almost embarrassed tone in Luffy's voice finally cut through Zoro's sleep-fog. He reopened his eye and properly analyzed the situation.
The moonlight illuminated Luffy standing there, with pale skin and half-lidded eyes glowing a faint crimson gleam, his black irises twinged with a splash of ruby red. His supernatural eyes were always visible when his instincts kicked in.
Luffy's lips were pulled apart in a visible strain.
And visible enough—fangs.
Right. He wasn't hungry for food.
It had taken the crew some time to adjust when their captain finally admitted what he was. A vampire. He wasn't the sorybook monster Usopp feared he'd turn out to be, but still, there was something ancient and hungry beneath all the warmth and chaos that made Luffy.
However, the fact that Luffy wasn’t entirely human became another rhythm aboard the Sunny. Their captain had always been unusual. Admittedly, the revelation was bizarre at first, but eventually ordinary.
To them, Luffy was still Luffy. Their captain. Their idiot. Their friend. He was still the boy who gave them freedom.
Even with blood on his mouth.
The Straw Hat Pirates had settled into a routine around their captain's condition. Chopper, naturally, handled medical concerns. He kept meticulous notes clipped to the health charts and constantly monitored their iron levels. Everyone, sans Brook, Franky, and Chopper, gave Luffy blood. He developed tonics and strictly implemented the rotation-between-members rule, which ensured Luffy was being well fed without making someone else sick.
The tiny doctor also had the help of Sanji, who barked at everyone about eating better for the captain's sake. Sanji happily added iron-rich meals to their diets to supplement the constant blood-giving. As well as Nami, who got into the habit of keeping track of who donated blood recently and whose turn was up.
Most days, Luffy managed just fine. He mostly fed in port towns when he could, feeding from other pirates whenever they docked because criminals weighed the least on his conscience.
But out at sea, there were stretches where no islands appeared for days at a time. That's where his crew stepped in.
In the beginning, Luffy didn't ask for blood because he would rather starve himself than feed off his friends. It wouldn’t be until someone noticed him getting pale and sluggish that they knew.
Their captain had spilled blood for every single one of them. He'd made a habit of recklessly throwing himself into impossible battles without hesitation and stood between them and death over and over again.
Yet sitting in front of someone he loved while their pulse beat against his tongue made guilt coil inside him like barbed wire.
He always noticed the marks, the unintentional bruising against their skin, or the bandages Chopper would carefully apply. Sometimes, it was the lingering exhaustion in their faces, because no matter how much they insisted they were fine, Luffy could never stop seeing evidence that he had taken something vital from them.
They never hesitated around him. Not even Usopp and Nami, who'd been the most skittish initially. It alarmed Luffy how quickly they granted him their surrender and exposed their throats or carelessly stuck their wrist out for him. He didn't think his friends understood just how vicious vampire instincts truly were. Hunger easily distorted thoughts, and the scent of fresh blood could become overwhelmingly irresistible, frighteningly fast.
Luffy’s greatest fear was that one day he might not be able to stop in time, or at all.
However, his crew stepped in regardless. No one was going to let their captain starve.
The swordsman pushed himself upright. "'C'mere then," he muttered, "dramatic little parasite."
Despite calling him that, seeing Luffy like this always stirred something protective in the Vice-Captain.
For Zoro, loyalty had never been complicated. If someone mattered to him, he protected them. If they needed him, he gave what he could. He gladly stood between his captain and danger with his swords drawn, taking wounds if it kept Luffy standing. That kind of devotion came easily to him. Pain didn't matter if it served a purpose. Luffy was his captain. Even before he learned the truth about his appetite for human blood, he had already decided he would make sure the boy who freed him achieved his dream to become King of the Pirates.
Even if that meant he had to become a stepping stone to the throne Luffy had his heart set on.
Even if it meant giving his life for his, like he was ready to on Thriller Bark island.
The vampire revelation changed nothing.
Luffy approached Zoro and carefully lowered himself onto him, straddling the swordsman's lap without hesitation. The first few times Luffy drank directly from him had been awkward and uncertain, but it had settled into something familiar between them, something delicate despite the lethal danger hidden beneath Luffy's smile.
Luffy’s fingers slid beneath the green Kimono, and he pushed the fabric aside carefully. Luffy was always careful with them.
Zoro adjusted his grip around Luffy’s waist and tilted his head to the side to give him better access to his neck.
Luffy carried his hunger like shame, and Zoro hated having to see him lose against himself. So, he never treated feeding like something ugly. Zoro understood sacrifice. This was just another way he could protect his captain. To him, it wasn't much different from every scar carved across his body in Luffy's name.
If his captain needed blood to survive, then Zoro would gladly bleed.
Luffy pressed his face into the crook of his neck. He nuzzled the warm skin, not biting yet. That was another thing the crew had discovered about their captain. He had preferences in blood. According to Luffy, each one of them had a scent unique only to them, and apparently, their Vice-Captain smelled the best to him.
Sanji could technically give more blood without feeling faint afterward. Chopper said it was because Sanji recovered blood volume faster than the rest of them. The cook always made a dramatic production out of it, too, grumbling about having better blood than that stupid marimo.
However, in this case, more didn't necessarily mean better. Their captain always chose Zoro first whenever he could.
Luffy continued to nose Zoro's exposed throat, breathing him in slowly. Anticipation curled low in the swordman's stomach. The motion was strangely tender, almost cat-like. Affectionate enough to make Zoro forget what came next.
Even after all this time, the sensation of sharp fangs pressing against his skin made Zoro tense automatically.
The bite itself was quick. Luffy bit down, and his vampiric fangs pierced his flesh in two precise points. Zoro hissed softly through his teeth as pain flared—quick and hot. The sting became more pressure than pain in seconds.
One of Luffy's bites barely registered compared to the injuries he endured regularly. Still, Zoro's hands momentarily tightened around Luffy's waist to ground himself.
Luffy made a soft, pleased sound at the first taste of blood, and damn him for it, because it always affected Zoro more than it should.
Luffy pulled back, just enough to grin against his neck, eyes half-shut. "You taste good." A faint smear of red stained the corner of his mouth, his fangs visible as he smiled.
Zoro huffed and tipped his head back against the wall behind him.
The bite was sharp and immediate, but the sensation that followed lasted even after the duration of the feeding.
Rapid spurts of venom slipped into Zoro's bloodstream in traces too small to damage but impossible to ignore. Chopper said it was convenient when the crew reported that it relaxed them, though he warned them repeatedly not to rely on the sensation of the toxins too much. The venom weakened resistance, softened struggling bodies, and slowed reaction time until escape became impossible.
Zoro understood this was meant to make him incapable while Luffy fed.
Only for Zoro, there was no actual fear in him for the venom to smother.
That made the sensation different. Exhilarating. Every time those fangs pressed into his skin, his body answered with immediate surrender.
Every muscle in Zoro's body loosened against his will at first as the tingling numbness robbed him of his autonomy. The liquid venom spread outward in ripples, enveloping him until every inch of him felt weighted and loose. The constant tension he carried dissolved, dulling the ache of old scars and the relentless alertness he lived with. It wrapped around his nervous system like velvet, coating every neurological signal until the world felt distant and dreamlike.
Zoro's sword hand twitched before slipping and going limp beside him. The other remained loosely on Luffy's waist.
His thoughts dulled. The deck beneath them, the sea beyond the Sunny, the warm summer night breeze entering through the open window, everything faded beneath the singular awareness of Luffy. For a brief stretch of time, he could sit with his captain and feel absolutely nothing except heaviness as his mind drifted out of focus.
It should have unsettled him.
There was something so adrenaline boosting in willingly letting something designed to overpower him seep through his veins.
The irony wasn't lost on him. Submitting to it should have felt humiliating, but in his captain's hands, the trust twisted it into comfort.
A normal victim would panic the moment the paralysis began. Every instinct would scream that something bad was happening as they inevitably lost control over their cognitive functions.
But Zoro had never felt that terror when Luffy bit him. Not once.
Even when the numbness spread through his arm. Even when his fingers stopped responding properly. Even when his body grew sluggish beneath the captain's body.
Luffy's grip occasionally tightened involuntarily.
But this was Luffy, and Luffy never took more than he was allowed. He never lost control enough to truly hurt them.
That made it more compulsive. Zoro's body learned quickly that the paralysis would never end in death, as it had for countless pirates who were unfortunate enough to become Luffy's sustenance, so instead of trepidation, it answered with anticipation. The bite became associated with something they mutually benefited from; Luffy got to eat, and Zoro got a release. He easily relaxed beneath Luffy's hold because some traitorous part of him already knew the overwhelming calm that followed.
And it left him drunk on it every single time.
Zoro never spoke about it to the others, including Luffy himself. He doubted he could explain it even if he tried. Not without getting concerned looks and a scolding from Chopper, who warned him not to do exactly what he was doing.
They all experienced the effects of the venom. However, could the other Straw Hats truly experience it from his point of view?
Could any of the other Straw Hats truly grasp how the venom made him feel? How it made the world blur pleasantly. How his thoughts slowed until all that remained was the steady awareness of Luffy near him, on him.
Sometimes, after days passed without a feeding because it wasn’t his turn, Zoro caught himself missing the dizzy intoxication that spread through his head. Missing the heavy drag behind his eyelids and the deep calm that only came from surrendering completely to someone he trusted.
It was so damn addictive. No sake could ever compare to the high he got from Luffy's venom.
And perhaps that was the dangerous thing about it. The fact that Zoro would willingly bare his throat for something that could easily kill him. Much like a vice, this could very well lead him to ruin, but he found solace in knowing he wouldn't go there without reaching nirvana first.
For someone so impulsive in every other part of life, feeding wasn't something Luffy got ahead of himself on. His mouth stayed latched against Zoro's neck while he swallowed in slow pulls instead of greedy ones. Zoro could actually feel the rhythm of it—the subtle pull of blood leaving his body every time Luffy swallowed. He could feel the breathless inhales and exhales fanning over his skin between drinks.
Zoro exhaled through his nose.
"There you go," he said, just as breathlessly. He moved his hand from Luffy's hip, his movement languid and delayed, and rested it on the back of Luffy's head, fingers sinking into disheveled black hair to keep him there, as if Luffy would pull away prematurely. "My captain."
Luffy hummed happily against his neck. His fingers tightened in Zoro's kimono. The shared intimacy wasn't lost on him. The closeness. The vulnerability. The necessity of trust. Though neither spoke about it directly.
The first few times he fed from Zoro, he chalked the strange heat in his stomach as nothing. It wouldn't be the first time good blood made him behave oddly. However, he eventually realized it only happened with Zoro.
Only Zoro's scent seemed to have its own gravitational pull.
Only Zoro's blood made his fangs ache even when he wasn't hungry.
Only Zoro made him want to touch.
Only Zoro drove him insane in a way he didn't understand. Every second required conscious effort not to lose control because of how badly he wanted more.
Luffy had fed from the others plenty of times now. His crew treated feeding for what it was: a necessity. They understood the importance, but there was always a degree of practical separation to it.
With Zoro, it was different. There was always tension that neither of them knew how to address. Not the way Zoro's breath would hitch, nor the way Luffy would end up pressed against him.
Luffy liked it. He was drawn to the way Zoro's hands rested on him or sometimes wandered without thinking. He liked the low exhale Zoro made whenever the venom started softening the edges of his usual gruff attitude.
Zoro never pushed him away, even when things drifted into something more intimate than they should be. It blurred the lines between what was acceptable between friends.
Usopp, unfortunately, once walked in on them and found Luffy pressed between the wall and Zoro's body, both heavily flushed. Luffy had his face buried in the swordsman's neck. Zoro, heavily panting, looked seconds away from erupting. Nothing had happened, but that was a mere glimpse at how easily they lost themselves in the act.
Luffy still didn't fully understand why feeding from Zoro made his chest feel tight and warm, or what compelled him to stay close afterward instead of darting off with his usual restless energy. He didn't know why his stomach felt funny whenever Zoro looked at him with sleepy, venom-heavy eyes. Or why he always wanted more of this nameless thing they shared.
He only knew that he liked it.
The crow's nest grew quiet except for the creak of the ship and the quiet sounds of small gulps and slow breathing, confidential between them and the stillness of the night.
Luffy fed just enough to satisfy the ache without draining too much. Those were the rules.
Eventually, the pulling sensation slowed.
Luffy rested his forehead against Zoro's shoulder as he caught his breath. The aftermath often left him boneless with relief.
"...Better?" Zoro slurred, half-drunk.
"Alright. Go bother someone else now."
Luffy laughed quietly, warm breath ghosting across Zoro's collarbone. It smelled strongly of iron from the blood he just consumed.
When he didn't make an effort to get up, Zoro spoke up. Luffy no doubt intended to spend the remainder of the night using him as a mattress.
"Mmm," Luffy whined, "but I'm sleepy."
"Then go to your hammock."
"But Zoro is more comfy," the young captain insisted, pulling back to face him with a pout. Luffy looked wrecked in the softest way possible. The sight alone sent a jolt of pleasure through Zoro.
The swordsman exhaled slowly through his nose to ground himself before his body announced his arousal. Luffy was right on his lap. He would definitely feel it.
And that would truly mortify Zoro.
Still, he took pride in knowing he had done that. Not Sanji. Not Nami. Not Robin.
Luffy preferred his blood.
After a moment, Zoro sighed in defeat and let him stay there. He couldn't get him off even if he tried. His acceptance wasn't a matter of bending to the captain's will, but rather the venom, still in his system, impeding his ability to shove him off. Its effects would linger as it gradually faded for another hour or so.
Luffy enthusiastically snuggled impossibly closer.
Within minutes, the exhaustion hit Luffy fully once more. Zoro felt the exact moment his captain drifted off. His cheek lay pressed against his shoulder, his body warm and loose in the swordsman’s lap.
The Vice-Captain looked down at him quietly, smiling softly to himself. The moon bathed them in pale light, catching the faint smear of red on the corner of Luffy's mouth.
It was ridiculously cute for someone who could easily rip another person’s throat apart.
The venom buzzed pleasantly through Zoro's veins, leaving him relaxed and tipsy as he adjusted his grip on Luffy more securely. Luffy made a sound in his sleep but didn't wake.
"Tch," Zoro muttered fondly.
Out in the open sea, beneath the sky as endless as the sea, Zoro settled back to keep watch over the tranquil night with his sleeping captain tucked safely against his chest.